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# Test2::Manual::Tooling::FirstTool

Write your first tool with Test2.

## DESCRIPTION

This tutorial will help you write your very first tool by cloning the `ok()`
tool.

## COMPLETE CODE UP FRONT

```perl
package Test2::Tools::MyOk;
use strict;
use warnings;

use Test2::API qw/context/;

use base 'Exporter';
our @EXPORT = qw/ok/;

sub ok($;$@) {
    my ($bool, $name, @diag) = @_;

    my $ctx = context();

    return $ctx->pass_and_release($name) if $bool;
    return $ctx->fail_and_release($name, @diag);
}

1;
```

## LINE BY LINE

- sub ok($;$@) {

    In this case we are emulating the `ok()` function exported by
    [Test2::Tools::Basic](../../Tools/Basic.md).

    `ok()` and similar test tools use prototypes to enforce argument parsing. Your
    test tools do not necessarily need prototypes, like any perl function you need
    to make the decision based on how it is used.

    The prototype requires at least 1 argument, which will
    be forced into a scalar context. The second argument is optional, and is also
    forced to be scalar, it is the name of the test. Any remaining arguments are
    treated as diagnostics messages that will only be used if the test failed.

- my ($bool, $name, @diag) = @\_;

    This line does not need much explanation, we are simply grabbing the args.

- my $ctx = context();

    This is a vital line in **ALL** tools. The context object is the primary API for
    test tools. You **MUST** get a context if you want to issue any events, such as
    making assertions. Further, the context is responsible for making sure failures
    are attributed to the correct file and line number.

    **Note:** A test function **MUST** always release the context when it is done,
    you cannot simply let it fall out of scope and be garbage collected. Test2 does
    a pretty good job of yelling at you if you make this mistake.

    **Note:** You **MUST NOT** ever store or pass around a _real_ context object. If
    you wish to hold on to a context for any reason you must use clone to make a
    copy `my $copy = $ctx->clone`. The copy may be passed around or stored,
    but the original **MUST** be released when you are done with it.

- return $ctx->pass\_and\_release($name) if $bool;

    When `$bool` is true, this line uses the context object to issue a
    [Test2::Event::Pass](../../Event/Pass.md) event. Along with issuing the event this will also
    release the context object and return true.

    This is short form for:

    ```perl
    if($bool) {
        $ctx->pass($name);
        $ctx->release;
        return 1;
    }
    ```

- return $ctx->fail\_and\_release($name, @diag);

    This line issues a [Test2::Event::Fail](../../Event/Fail.md) event, releases the context object,
    and returns false. The fail event will include any diagnostics messages from
    the `@diag` array.

    This is short form for:

    ```perl
    $ctx->fail($name, @diag);
    $ctx->release;
    return 0;
    ```

## CONTEXT OBJECT DOCUMENTATION

[Test2::API::Context](../../API/Context.md) is the place to read up on what methods the context
provides.

## SEE ALSO

[Test2::Manual](../../Manual.md) - Primary index of the manual.

## SOURCE

The source code repository for Test2-Manual can be found at
`https://github.com/Test-More/test-more/`.

## MAINTAINERS

- Chad Granum <exodist@cpan.org>

## AUTHORS

- Chad Granum <exodist@cpan.org>

## COPYRIGHT

Copyright Chad Granum <exodist@cpan.org>.

This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.

See `http://dev.perl.org/licenses/`